1. Field of the Invention
The present invention relates to tendon anchors. More specifically, it relates to tendon anchors utilized to attach tendons to one or more bones without sutures and through a single bore drilled into the bone.
2. Description of the Prior Art
The need to effectively and efficiently attach a tendon to a bone is absolutely critical in a number of orthopedic surgical procedures. The most common current practice is to utilize a device called a suture anchor to attach a suture to the bone and the thereafter tie the tendon to the suture thereby making the attachment of the tendon to the bone. Examples of this practice are set forth in U.S. Pat. Nos. 5,961,538; 5,944,724; 5,906,624; and 5,904,704. While such techniques are reasonably effective, the use of suture anchors is overly time consuming and creates unnecessary risks of failure. For example, the suture may become detached from the anchor or the tendon and the process of suturing the tendon to the anchor may actually weaken the strength of the tendon itself or cause it to tear. It is believed that a better technique would involve a direct attachment of the tendon itself to a tendon anchor which is secured within the bone.
One known process which is believed to be a step in the right direction is disclosed in a publication entitled xe2x80x9cBone Mulch Screw/WasherLoc Device For the New Millenniumxe2x80x9d published by Arthrotek, a Biomet Company. The publication is undated but is believed to have been published in early 2000 and not earlier than the later part of 1999. This publication discloses an ACL reconstruction technique in which a tendon is ultimately attached directly to the bone by means of tendon anchors. While sutures are not utilized to attach the tendon to the bone, the process still requires the use of a suture (pp. 9-10) attached to one end of the tendon to pull the tendon over a transverse cross beam of the femoral anchor. Such a process is overly complex and unnecessarily time consuming.
Further, the Arthotek device itself is overly complex and utilizes at least one tendon anchor which requires drilling bores into two separate bores into the femur, one longitudinally through which the tendon is threaded and one transversely to provide a cross beam over which the tendon is passed (see FIG. 25 of publication). Drilling extra bore into the bone takes more time, requires precision to make certain that the two bore holes intersect, causes increased trauma to the patient and can weaken the overall structure of the bone. Thus, while this technique provides an improvement over prior art devices which require suturing a tendon to a suture anchor (sometimes called bone anchor), there remains a need for a simple, easy to install tendon anchor which does not require sutures at all during the installation procedure and which only require the drilling of a single bore into the bone.
The present invention meets this need by providing a number of differently designed tendon anchors which each include a channel to receive and hold a tendon which is inserted into a single bore in the bone with the anchor. Thus, no sutures are required and only a single bore hole is needed.
In its simplest form, the present invention provides a tendon anchor for attaching a tendon to at least one bone without sutures within a bore drilled in into said at least one bone comprising a first tendon anchor adapted for insertion into said bore of a first bone, said first tendon anchor having a channel provided therein for receiving and holding a central portion of a tendon during insertion and when in final position in the bore of said first bone with opposite ends of the tendon extending out of the singular bore; and a first securing means associated with said first tendon anchor for moving at least a part of the first tendon anchor radially outward to securely engage the first tendon anchor and the central portion of the tendon to the first bone by urging at least a part of the first tendon anchor against a cylindrical wall portion of said bore in said first bone.
Preferably, said first tendon anchor is generally cylindrical in shape with a cylindrical outer wall and has a crescent shaped recess therein, said recess extending longitudinally along a cylindrical wall portion thereof from one end portion of the first tendon anchor to a location at least two-thirds of the distance toward an opposite end portion thereof.
Preferably, said first securing means is a first tapered screw adapted to be received between a cylindrical wall of the bore in said first bone and said threaded recess, whereby tightening said first screw causes one side of the first screw to embed itself into a cylindrical wall of the bore and an opposite side of the first screw urges a portion of the first tendon anchor opposite said crescent shaped recess and the entire tendon anchor radially outward against an opposite cylindrical wall of the bore.
In a presently preferred embodiment of the invention, said cylindrically outer wall portion of said first anchor means is provided with outward projections thereon to aid in engaging said outer wall portion of the first tendon anchor to the cylindrical wall of the bore.
Preferably, said cylindrically shaped first tendon anchor has a transverse hole therein which forms said channel, said transverse hole extending from opposite cylindrical walls and positioned transversely to the crescent shaped recess and wherein said tendon is threaded through said transverse hole whereby a central portion thereof is positioned within said transverse hole.
In many cases, the invention will utilize two tendon anchors. In such cases, a second tendon anchor is provided which is adapted for insertion into a bore drilled into a second bone; and a second securing means associated with said second tendon anchor for moving at least a part of the second tendon anchor radially outward to securely engage the second tendon anchor and the end portions of the tendon to the second bone by urging at least a part of the second tendon anchor against a cylindrical wall portion of said bore in said second bone.
Preferably, said second tendon anchor is also generally cylindrical in shape with a cylindrical outer wall and has a crescent shaped recess therein, said recess extending longitudinally along and entire cylindrical wall portion thereof from one end portion of the second tendon anchor to an opposite end portion thereof.
Preferably, said second securing means is a second tapered screw adapted to be received between a cylindrical wall of the bore in said second bone and said threaded recess, whereby tightening said second screw causes one side of the second screw to embed itself into a cylindrical wall of the bore in the second bone and an opposite side of the second screw urges a portion of the second tendon anchor opposite said crescent shaped recess and the entire second tendon anchor radially outward against an opposite cylindrical wall of the bore in said second bone.
In the preferred embodiment, said cylindrically outer wall portion of said second anchor means is provided with outward projections thereon to aid in engaging said outer wall portion of the second tendon anchor to the cylindrical wall of the bore of the second bone.
Preferably, said cylindrically shaped second tendon anchor has notches therein to receive the opposite ends of said tendon and said ends of said tendon are compressed and held in place between the cylindrical wall of the bore of the second bone and said cylindrical outer wall of the second tendon anchor.
In an alternative embodiment of the invention, said first tendon anchor has a generally elongated rectangular shape with opposite ends thereof having engaging portions thereon adapted to engage into the cylindrical wall of the bore in the first bone, said first tendon anchor having a securing means in the form of a transverse hole therein adapted to receive a central portion of said tendon, said hole also constituting said channel, said hole being closer to one end of the first tendon than the other anchor and closer to one side of the tendon anchor than the other, whereby said first tendon anchor with a tendon threaded into said hole therein is inserted into the bore in the first bone longitudinally and upon exerting force upon the ends of the tendon, said first tendon anchor rotates to a partially transverse position within the bore thus forcing said engaging portions into the cylindrical bore in the first bone thereby securing the tendon in said first bone.
In yet another embodiment of the invention, said first tendon anchor is formed of a first elongated member and a second elongated member, said first and second members each having an engaging portion on at least one end thereof adapted to engage into the cylindrical wall of the bore in the first bone, said first and second members having a channel provided in one end thereof for receiving and holding a central portion of a tendon during insertion and when in final position in the bore in said first bone, said first and second elongated members engaging one another at a location intermediate the end portions thereof and adapted to move relative to one another in a scissor like fashion whereby said members are inserted into the bore of the first bone in a substantially closed scissor position with the central portion of the tendon engaged and held in the channel of each member and whereby exerting force upon the ends of the tendon causes the members to move to an open scissor position forcing the engaging portion of each member into the cylindrical bore in the first bone thereby securing the tendon in said first bone.
In this embodiment, exerting greater force on the tendon ends caused said engaging portion to embed more deeply into the cylindrical bore in the first bone thereby more securely holding the tendon in said first bone.